The research of L-type matching filter parameters

The work of L-type matching filters for different methods of detecting the PLL feedback signal and the filter parameter influence on oscillation amplitude of piezoelectric transducer are investigated in this research. The equivalent scheme of quadripole with mechanical resistance load composed of filter and a piezoelectric transducer is designed. The expressions for the input filter impedance and oscillation amplitude of piezoelectric transducer on the input voltage amplitude are obtained by the analysis of the T-shaped equivalent circuit. Relations for matching filter inductance for piezoelectric transducer working at the serial and parallel resonance frequencies are calculated analyzing the expression for the input impedance. Inappropriate use of L-type filter for piezoelectric transducer working at the serial resonance frequency is shown theoretically. The possibility of piezoelectric transducer operating mode with independent of the mechanical load amplitude of mechanical vibrations is given. The adequacy of mathematical modeling is confirmed by the experimental results.